Astronomers believe that Europa, one of Jupiter's moons, has a huge ocean beneath its icy surface. They have theorized that water, salts and gasses that have dissolved into that ocean rise to the surface, generating the enigmatic geological formations associated with the red-tinged formations seen on the moon's surface.

Aluminum (or aluminium) is a soft, lightweight, silvery metal. It is an element in the boron group on the periodic table of elements, with the symbol Al and atomic number 13. On the earth's crust, aluminum is the most abundant metal, and the third most abundant of all elements on the earth's crust, after oxygen and silicon. It accounts for 8% of the weight of the Earth's solid surface.
Because aluminum is a highly reactive metal, it doesn't occur in nature in a pure form. Aluminum forms a...

Dolomite is a mineral (formula CaMg(CO3)2) consisting of a calcium magnesium carbonate found in crystals and in beds as dolostone. A pure form of dolostone would be rare, however; it usually intergrades with limestone and is referred to as dolomitic limestone, or in old U. S. geologic literature as magnesian limestone.
Dolomite has physical properties similar to those of the mineral calcite, but is less soluble in hydrochloric acid.
There is uncertainty as to the cause of its formation,...

Magnesium is the chemical element in the periodic table that has the symbol Mg and atomic number 12. Magnesium is the eighth most abundant element and constitutes about 2% of the Earth's crust, and it is the third most plentiful element dissolved in seawater. This alkaline earth metal is primarily used as an alloying agent to make aluminium-magnesium alloys.
Notable characteristics
Magnesium is a fairly strong, silvery-white, light-weight metal (one third lighter than aluminium) that...

Talc is a mineral composed of hydrated magnesium silicate with the chemical formula H2Mg3(SiO3)4 or Mg3Si4O10(OH)2. It occurs as foliated to fibrous masses, its monoclinic crystals being so rare as to be almost unknown. It has a perfect basal cleavage, the folia non-elastic although slightly flexible. It is sectile and very soft, with a hardness of 1 (Talc is the softest known solid). It has a specific gravity of 2.5 - 2.8, a waxlike or pearly luster, and is translucent to opaque. Its color...

A pivoted catch designed to fall into a notch on a ratchet wheel so as to allow movement in only one direction (e.g. on a windlass or in a clock mechanism), or alternatively to move the wheel in one direction.